Southern Pinellas County, FL

Can you build in a regulatory floodway?

During the planning phase of any construction project, it is imperative to verify if a project is located within an area identified as a regulated floodway or floodplain as defined by the Federal Emergency Management Agency (FEMA).
Most construction activities within a regulated floodway or floodplain require coordination with FEMA and the local Floodplain Administrator (FPA). These activities include new building construction, existing building expansion, clearing land, placing fill, grading land, mining, dredging, drilling, placement of mobile homes, and more.
Many developers are often surprised to learn that coordination with FEMA is necessary even for excavations in the floodplain or floodway. If proper coordination and permitting have not been completed, then more issues can await during construction.
Floodways vs. Floodplains
FEMA defines a Regulatory Floodway as the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height. Communities must regulate development in these floodways to ensure that there are no increases in upstream or downstream flood elevations due to construction activities.
Floodplains are recognized on the FEMA’s Flood Insurance Rate Maps (FIRMs) as Special Flood Hazard Areas (SFHAs). SFHAs are defined as the area that will be inundated by a flood event having a 1-percent chance of being equaled or exceeded in any given year. The 1-percent annual chance flood is also referred to as the base flood or 100-Year Flood.
SFHAs are labeled as Zone A, Zone AO, Zone AH, Zones A1-A30, Zone AE, Zone A99, Zone AR, Zone AR/AE, Zone AR/AO, Zone AR/A1-A30, Zone AR/A, Zone V, Zone VE, and Zones V1-V30.
Moderate flood hazard areas, labeled Zone B or Zone X (shaded) are also shown on the FIRM, and are the areas between the limits of the base flood and the 0.2-percent annual chance (or 500-year) flood. The areas of minimal flood hazard, which are the areas outside the SFHA and higher than the elevation of the 0.2 percent annual chance, are labeled Zone C or Zone X (unshaded).